Fail with comprehensible error message if path dependencies do not exist

src/poetry/puzzle/provider.py

@@ -50,6 +50,7 @@
     from poetry.core.packages.directory_dependency import DirectoryDependency
     from poetry.core.packages.file_dependency import FileDependency
     from poetry.core.packages.package import Package
+    from poetry.core.packages.path_dependency import PathDependency
     from poetry.core.packages.url_dependency import URLDependency
     from poetry.core.packages.vcs_dependency import VCSDependency
     from poetry.core.version.markers import BaseMarker
@@ -390,6 +391,7 @@ def get_package_from_vcs(
         )
 
     def _search_for_file(self, dependency: FileDependency) -> Package:
+        dependency.validate(raise_error=True)
         package = self.get_package_from_file(dependency.full_path)
 
         self.validate_package_for_dependency(dependency=dependency, package=package)
@@ -420,6 +422,7 @@ def get_package_from_file(cls, file_path: Path) -> Package:
         return package
 
     def _search_for_directory(self, dependency: DirectoryDependency) -> Package:
+        dependency.validate(raise_error=True)
         package = self.get_package_from_directory(dependency.full_path)
 
         self.validate_package_for_dependency(dependency=dependency, package=package)
@@ -652,6 +655,11 @@ def complete_package(
                     if locked is not None and locked.package.is_same_package_as(dep):
                         continue
                     self.search_for_direct_origin_dependency(dep)
+        else:
+            for dep in _dependencies:
+                if dep.is_file() or dep.is_directory():
+                    dep = cast("PathDependency", dep)
+                    dep.validate(raise_error=True)
 
         dependencies = self._get_dependencies_with_overrides(
             _dependencies, dependency_package

tests/console/commands/test_install.py

@@ -14,6 +14,7 @@
 
     from poetry.poetry import Poetry
     from tests.types import CommandTesterFactory
+    from tests.types import FixtureDirGetter
     from tests.types import ProjectFactory
 
 
@@ -69,6 +70,22 @@ def tester(
     return command_tester_factory("install")
 
 
+def _project_factory(
+    fixture_name: str,
+    project_factory: ProjectFactory,
+    fixture_dir: FixtureDirGetter,
+) -> Poetry:
+    source = fixture_dir(fixture_name)
+    pyproject_content = (source / "pyproject.toml").read_text(encoding="utf-8")
+    poetry_lock_content = (source / "poetry.lock").read_text(encoding="utf-8")
+    return project_factory(
+        name="foobar",
+        pyproject_content=pyproject_content,
+        poetry_lock_content=poetry_lock_content,
+        source=source,
+    )
+
+
 @pytest.mark.parametrize(
     ("options", "groups"),
     [
@@ -291,3 +308,24 @@ def test_install_logs_output_decorated(tester: CommandTester, mocker: MockerFixt
     )
     assert tester.status_code == 0
     assert tester.io.fetch_output() == expected
+
+
+@pytest.mark.parametrize("options", ["", "--without dev"])
+@pytest.mark.parametrize(
+    "project", ["missing_directory_dependency", "missing_file_dependency"]
+)
+def test_install_path_dependency_does_not_exist(
+    command_tester_factory: CommandTesterFactory,
+    project_factory: ProjectFactory,
+    fixture_dir: FixtureDirGetter,
+    project: str,
+    options: str,
+):
+    poetry = _project_factory(project, project_factory, fixture_dir)
+    poetry.locker.locked(True)
+    tester = command_tester_factory("install", poetry=poetry)
+    if options:
+        tester.execute(options)
+    else:
+        with pytest.raises(ValueError, match="does not exist"):
+            tester.execute(options)

tests/console/commands/test_lock.py

@@ -204,6 +204,63 @@ def test_lock_no_update_path_dependencies(
     assert {p.name for p in packages} == {"quix", "sampleproject"}
 
 
+@pytest.mark.parametrize("update", [True, False])
+@pytest.mark.parametrize(
+    "project", ["missing_directory_dependency", "missing_file_dependency"]
+)
+def test_lock_path_dependency_does_not_exist(
+    command_tester_factory: CommandTesterFactory,
+    project_factory: ProjectFactory,
+    fixture_dir: FixtureDirGetter,
+    project: str,
+    update: bool,
+):
+    poetry = _project_factory(project, project_factory, fixture_dir)
+    locker = Locker(
+        lock=poetry.pyproject.file.path.parent / "poetry.lock",
+        local_config=poetry.locker._local_config,
+    )
+    poetry.set_locker(locker)
+    options = "" if update else "--no-update"
+
+    tester = command_tester_factory("lock", poetry=poetry)
+    if update or "directory" in project:
+        # directory dependencies are always updated
+        with pytest.raises(ValueError, match="does not exist"):
+            tester.execute(options)
+    else:
+        tester.execute(options)
+
+
+@pytest.mark.parametrize("update", [True, False])
+@pytest.mark.parametrize(
+    "project", ["deleted_directory_dependency", "deleted_file_dependency"]
+)
+def test_lock_path_dependency_deleted_from_pyproject(
+    command_tester_factory: CommandTesterFactory,
+    project_factory: ProjectFactory,
+    fixture_dir: FixtureDirGetter,
+    project: str,
+    update: bool,
+):
+    poetry = _project_factory(project, project_factory, fixture_dir)
+    locker = Locker(
+        lock=poetry.pyproject.file.path.parent / "poetry.lock",
+        local_config=poetry.locker._local_config,
+    )
+    poetry.set_locker(locker)
+
+    tester = command_tester_factory("lock", poetry=poetry)
+    if update:
+        tester.execute("")
+    else:
+        tester.execute("--no-update")
+
+    packages = locker.locked_repository().packages
+
+    assert {p.name for p in packages} == set()
+
+
 @pytest.mark.parametrize("is_no_update", [False, True])
 def test_lock_with_incompatible_lockfile(
     command_tester_factory: CommandTesterFactory,

tests/console/commands/test_show.py

@@ -8,6 +8,7 @@
 from poetry.core.packages.dependency_group import DependencyGroup
 
 from poetry.factory import Factory
+from poetry.utils._compat import tomllib
 from tests.helpers import MOCK_DEFAULT_GIT_REVISION
 from tests.helpers import get_package
 
@@ -2140,3 +2141,33 @@ def test_url_dependency_is_not_outdated_by_repository_package(
     # version in the repository.
     tester.execute("--outdated")
     assert tester.io.fetch_output() == ""
+
+
+@pytest.mark.parametrize(
+    ("project_directory", "required_fixtures"),
+    [
+        (
+            "deleted_directory_dependency",
+            [],
+        ),
+    ],
+)
+def test_show_outdated_missing_directory_dependency(
+    tester: CommandTester,
+    poetry: Poetry,
+    installed: Repository,
+    repo: TestRepository,
+):
+    with (poetry.pyproject.file.path.parent / "poetry.lock").open(mode="rb") as f:
+        data = tomllib.load(f)
+    poetry.locker.mock_lock_data(data)
+
+    poetry.package.add_dependency(
+        Factory.create_dependency(
+            "missing",
+            {"path": data["package"][0]["source"]["url"]},
+        )
+    )
+
+    with pytest.raises(ValueError, match="does not exist"):
+        tester.execute("")

tests/fixtures/deleted_directory_dependency/pyproject.toml

@@ -0,0 +1,10 @@
+[tool.poetry]
+name = "project-with-missing-directory-dependency"
+version = "1.2.3"
+description = "This is a description"
+authors = ["Your Name <you@example.com>"]
+license = "MIT"
+packages = []
+
+[tool.poetry.dependencies]
+python = "*"

tests/fixtures/deleted_file_dependency/pyproject.toml

@@ -0,0 +1,10 @@
+[tool.poetry]
+name = "project-with-missing-directory-dependency"
+version = "1.2.3"
+description = "This is a description"
+authors = ["Your Name <you@example.com>"]
+license = "MIT"
+packages = []
+
+[tool.poetry.dependencies]
+python = "*"

tests/fixtures/missing_directory_dependency/pyproject.toml

@@ -0,0 +1,13 @@
+[tool.poetry]
+name = "project-with-missing-directory-dependency"
+version = "1.2.3"
+description = "This is a description"
+authors = ["Your Name <you@example.com>"]
+license = "MIT"
+packages = []
+
+[tool.poetry.dependencies]
+python = "*"
+
+[tool.poetry.dev-dependencies]
+missing = { path = "./missing" }

tests/fixtures/missing_file_dependency/pyproject.toml

@@ -0,0 +1,13 @@
+[tool.poetry]
+name = "project-with-missing-directory-dependency"
+version = "1.2.3"
+description = "This is a description"
+authors = ["Your Name <you@example.com>"]
+license = "MIT"
+packages = []
+
+[tool.poetry.dependencies]
+python = "*"
+
+[tool.poetry.dev-dependencies]
+missing = { file = "missing-0.1.0-py2.py3-none-any.whl" }